LS performance: make BinaryTransitiveClosureCheck work in either direction

[eclipse-viatra-bot]

| --- | --- |
| Bugzilla Link | 563225 |
| Status | NEW |
| Importance | P3 enhancement |
| Reported | May 15, 2020 11:50 EDT |
| Modified | May 15, 2020 11:50 EDT |
| Version | 2.3.0 |
| Reporter | Gabor Bergmann |

Description

BinaryTransitiveClosureCheck operations in the LS backend (i.e. checking find foo+(x,y) whan x and y are known already) have suboptimal performance.

Right now, the executor only traverses from source to (transitive) targets, even though the other direction is just as feasible. There are cases where target-to-source would be preferable due to lower fan-outs, especially if each target has only one associated source (typical with transitive containment check). The planner should be able to choose the more favorable direction.